Karlsson did give San Jose a 1-0 lead at 10:23 when he scored from the right circle after receiving a pass from Barabanov.
Torey Krug tied it 1-1 at 12:31. After Thomas stripped the puck from Svechnikov at St. Louis' blue line, he passed to the trailer Krug for the snap shot from the left circle. It was his first goal in 24 games (Dec. 1).
Sammy Blais gave the Blues a 2-1 lead at 10:06 of the second period. William Eklund could not handle a pass by Karlsson at St. Louis' blue line, and Colton Parayko dove to poke the puck forward to Blais, who scored on a breakaway.
Hertl tied it 2-2 at 14:31. After Calle Rosen turned the puck over inside the Blues zone to Barabanov, he passed to Hertl, who scored blocker side from the high slot.
"It's always nice to score a goal," Hertl said. "But I still try to win the game every night. It's nice to finally have some chances and score some goals. I just have to keep working."
NOTES: Buchnevich has 13 points (four goals, nine assists) during a seven-game point streak. ... Karlsson has 83 points (20 goals, 63 assists) in 66 games this season, surpassing his NHL career high set in 2015-16 as a member of the Ottawa Senators. He is the second defenseman in NHL history to have eight or more seasons between 20-goal seasons (21 in 2014-15), joining Mathieu Schneider, who had an 11-year gap (20 goals in 1993-94 and 21 in 2005-06). ... Rosen had three blocked shots in 14:02 of ice time after being a healthy scratch for six games. … Kahkonen has lost four straight and is 0-6-1 in his past seven starts. … Blais has three goals in 13 games since being reacquired from the New York Rangers on Feb. 9. He did not score in 40 games with the Rangers this season.